Fuel injector



FUEL INJECTOR 2 Sheets-Sheet 1 Original Filed May 16, 1958 INVENTORSROLLIN J. M CRORY ROBERT W. KING O O O ROBERT M. CONKLIN 3,042,010 FUELINJECTQR Rollin J. McCrory, Worthington, and Robert W. King and RobertM. Conldin, Columbus, Ohio, assignors, by mesne assignments, to TheBattelie Development Corporation, Columbus, Ohio, a corporation ofDelaware Original application May 16, 195%, Ser. No. 735,795, new PatentNo. 2,959,159, dated Nov. S, 1960. Divided and this application Mar. 16,196i), Ser. No. 15,302

19 Ciaims. (Cl. l23--32) This invention relates to improvements in thefuel supply system for the free-piston engine, and, more particularly,to a fuel injection system especially adaptable to a free-piston engine.This is a divisional application of our copending application entitledFree-Piston Internal Combustion Apparatus, Serial No. 735,795, filed May16, 1958, now Patent 2,959,159, issued November 8, 1960. Free-pistonengines are those in which the reciprocating action of the piston, orpistons, is not mechanically restrained by the conventional connectingrod and crankshaft. Although most of the multipiston freepiston engineshave mechanical connections between the pistons to maintain the properphasing between the pistons, the end positions of the piston stroke arenot established by the mechanical connections. The end positions of thepiston stroke are established on each engine cycle by the energyreleased to the work article, or load, that is being driven by theengine, the energies of the combustion process, and the resilientrebound system.

Briefly described, the present invention includes means for pressurizingfuel in a fuel-injector device, means for retaining the fuel underpressure, reciprocal means to open communication means between the fuelinjector and the combustion cylinder of the engine allowing thepressurized fuel to be injected into the combustion cylinder. Thereciprocating action of the injector is especially suited to an enginewith no rotating parts and provides excellent timing of fuel injectionwith the combustion stroke of the engine.

One embodiment of this invention comprises a body member having adischarge outlet into the combustion cylinder of the engine and having aplurality of recesses. A plunger reciprocates in one of the recesses ofthe body member with resilient means to move the plunger in onedirection and actuator means to move the plunger in the oppositedirection. A diaphragm is disposed in another one of the recesses of thebody member partitioning the recess into a first and second chamber.Resilient means in the first chamber urges the diaphragm toward thesecond chamber. Fuel is supplied under pressure to the second chamberand to the plunger recess. The plunger recess communicates with thefirst chamber and the fuel discharge outlet. A conduit in the plungeralternately registers with the fuel supply and the communication withthe first chamber. The pressure in the first chamber is alternatedbetween the fuel pressure and the pressure of the combustion cylinderwhich flexes the diaphragm and injects fuel into the combustion cylinderof the engine.

Another embodiment of the invention comprises a body member having adischange outlet into the combustion cylinder of the engine, a pluralityof chambers, and a plunger reciprocal in a bore in the body member;resilient means disposed in the body member urging the plunger inmovement in one direction and actuator means engaging the plunger andoperable to move the plunger in the opposite direction; means forsupplying fuel and means for supplying air to the plunger bore atsuperatmospheric pressure; communication means between a first one ofthe chambers and the plunger bore, combore at a third position, thesecond conduit sequentially registering between the first chambercommunication means and the air supply means at a first position, withthe plunger bore at a second position, between the first chambercommunication means and the second chamber communication means at athird position with the second chamber communication means being open toatmos-.

phere at the first position.

A feature of the present invention is a fuel injection system controlledby the reciprocation of the engine system providing proper timing forfuel injection.

Another feature of this invention is a fuel injection system thatreceives the power for its operation in the form of direct mechanicaland hydraulic energy from the englue.

Still another feature of the present invention is a fuelinjection systemcapable of positively injecting a fuel charge into the combustionchamber under the control of means operated directly and properly timedin con neotion with the rapid reciprocation of the free piston.

Other features and objects of the invention will be apparent from theattached drawings, and the following description. This inventioncomprises apparatus and a method of applying the same, the preferredform of which is disclosed in the following description and attacheddrawings. Although the appanatus, structure, and method described andshown in detail refer with particularity to a fuel injection system fora single-cylinder, free-piston engine, it is apparent that thisinvention should not be limited thereto. The invention may be used forother purposes, where its features are advantageous.

In the drawings:

H6. 1 is an elevational, partially sectioned view of a free-pistonengine showing the fuel-injection system in connection therewith;

FIG. 2 is an elevational, partially sectioned view taken along the line2-2 of FIG. 1;

FIG. 3 is a sectional, elevational view of a diaphragm operated fuelinjector according to this invention;

FIG. 4 is a schematic elevational view of a fuel tank to be used withthis invention;

FIG. 5 is a sectional, elevational view of an air-blast fuel injectoraccording to this invention;

FIG. 6 is a partial sectional view of the air-blast fuel injector ofFIG. 5 with the plunger at a different position; and

FIG. 7 is a sectional, elevational view of another embodiment of anair-blast fuel injector according tothis invention.

Referring to FIGS. 1 and 2, a free-piston engine 50 comprises a block orframe 51 and a free piston 52 reciprocal therein. The frame 51 isprovided with an internally bored combustion cylinder 53 and provided incommunication therewith is a coaxial greater-diameter compressioncylinder 54. Closing the compression cylin- 3 and the combustioncylinder 53 by means of the exhaust ports 57.

An annular intake manifold 63 is also provided in the frame 51 at aposition further removed from the head end of the combustion cylinder.Communication is established between the combustion cylinder 53 and theintake manifold 63 by intake ports 58.

At the head end 64 the combustion cylinder 53 is provided with ignitionmeans 65, such as a spark plug. Centrally positioned on the axis of thecombustion cylinder 53, at the head end 64, is the fuel nozzle 66 of afuel injector, designated generally as 68.

An exhaust outlet 87 is provided at one position in the exhaust manifold62.

As shown in FIGS. 1 and 2, piston 52 is constructed with aminor-diameter portion 88 that is adapted to reciprocate in thecombustion cylinder 53, being sealed with the cylinder wall 61 by meansof piston rings 89. At the opposite end piston 52 is formed in agreater-diameter portion 90 which is adapted to reciprocate in acompression cylinder 54 and is sealed in connection therewith by meansof the piston ring 91. The minor-diameter portion 88 is provided with alongitudinal cam groove 93.

. The free-piston engine 50 shown in FIGS. 1 and 2 is provided with apiston rod 94 fastened to or formed integrally-with piston 52 andadapted to protrude through the base plate 55 and reciprocate thereinthrough a bushing 95 with a seal 102. The piston rod 94, shown in FIG.1, is constructed with a threaded end 96 to receive and hold areciprocating tool. I

Compression cylinder 54 is divided by the major-diameter portion orpiston flange 90 into a bounce chamher 111 on the one side (lower sidein FIG. 1) and a counterchamber 112 on the other side (upper side inFIG. 1). Since, in FIG. 1, the piston 52 is shown at its uppermosthead-end position, bounce chamber 111 is at its maximum volume, whilecounterchamber 112 is at minimum volume. On the other hand, in FIG. 2the piston is shown at the bottom of its stroke and bounce chamber 111is of minimum volume and counterchamber 112 is of maximum volume. Neareach end of the compression cylinder 54, pressure-relief valves 113 and114 are provided in the frame 51. Relief valve 113 is in communicationwith counterchamber 112 by means of a conduit 115. Relief valve 114 isin communication with bounce chamber 111 by means of a conduit 1 16.

At a position circumferentially removed from the relief valves 114 and115 is located an inlet air valve chamber 117 and a scavenge air valvechamber 118. Each of chambers 117 and 118 is formed from a recess in theframe 51 and a cover plate 119 and 120, respectively. Cover plates 119and 120* are held in place by suitable means, such as screws 121.

The inlet air valve chamber 117 is provided vw'th a reed-type inlet airvalve 122 adapted to open and close with respect to an inlet air valveport 123. Communication is provided between counterchamber 112 and valvechamber 117 by means of an inlet port 124.

On the opposite side a scavenge valve 125, of the reed type, is adaptedto open and close a scavenge air port 126 in communication withcounterchamber 112. A conduit 127 is provided in the frame 51 connectingthe intake manifold 63 with scavenge air valve chamber 118.

Bounce chamber 111 is connected to an accumulator 291 (FIG. 4) by meansof an accumulator line 128. This connection may be made at the frame 51by means of a suitable fitting 129 on a check valve 130 which isthreadedly received in the side of the frame 51.

At one side of the engine 50, a cam-follower actuator rod 139, having asuitable seal 137, is positioned in camfollower bore 59 forradialreciprocation when actuated by a cam follower 140 operating incam-follower groove 93.

As the piston 52 reciprocates longitudinally, cam follower 140 is causedto reciprocate radially with respect to the pistons 52 by the depth andcontour of cam groove 93. Actuator rod 139 engages an end 141 of arocker arm 142. At the opposite end, rocker arm 142 is in contact with aplunger or stem 143 of the fuel injector 68. A trunnion yoke 144pivotally supports rocker arm 142. Resilient means, such as a spring145, acting against a collar 146 urges actuator rod 139 into continuouscontact with the cam groove 93.

In the description of the engine 50 and the description of its operationto follow, reference may be made to the power stroke as the down strokeand the compression stroke as the up stroke. This is in conformity withthe position of the engine in' FIGS. 1 and 2. This terminology isemployed for descriptive convenience and defines no limitation of theposition of the engine, as the engine may be operated at anyorientation.

Operation In the combustion cycle of free-piston engine 50, up- Wardmovement of the piston compresses air which has been admitted from theintake manifold 63 through the intake ports 58. Fuel is admitted throughthe fuel nozzle 66, forming a combustible mixture which is ignited byspark plug 65 at or near the time the piston reaches headend positionshown in FIG. 1. Ignition and burning of the fuel forces the piston 52downward, making energy available at the connection 96 of piston rod 94.When the piston 52 passes exhaust ports 57 on the downward stroke,products of combustion are exhausted through these ports into exhaustmanifold 62. Continued downward progress of piston 52 opens intake ports58, permitting the admission of air to scavenge the combustion cylinder53.

During the downward stroke of the piston 52, air is compressed in bouncechamber 111, storing energy to return the piston 52 for the next upwardstroke. At the same time, inlet air valve 122 opens by reason of theless-than-atmospheric pressure created in counterchamber 112 by thedownward stroke of piston 52. Opening of inlet valve 123 admits air tothe counterchamber 1 12.

On the down stroke of piston 52, when the pressure in bounce chamber 111exceeds the pressure in accumulafor 2 91 and line 128 by an amountsufiicient to open check valve 131 air is pumped into the accumulatorfor operation of the fuel injector 63.

The compression energy of the air in bounce chamber 111 forces thepiston 52 up on the compression stroke. The air in counterchamber 112 iscompresesd causing scavenge air valve 125 to open and the air to beexpelled through the scavenge air port 126. Compressed air is forcedfrom scavenge air chamber 118 upward through conduit 127 into intake airmanifold 63 for operation of the combustion cycle of the engine. Afterthe majordiameter portion of piston 52 closes inlet port 124 andscavenge air port 126 on the upstroke, air is compressed incounterchamber 112, serving to help decelerate the piston to a stop atthe head-end position.

Pressure-relief valve 113 provides for a predetermined maximum pressurein counterchamber 112, and therefore, a fixed maximum energy return tothe system on the combustion stroke. Conduit of pressure-relief valve113 is located a short distance from the upper end of counterchamber112, and the remaining short distance provides a completely sealed aircushion for safety purposes. This air cushion prevents the piston frommaking contact with the ends of counterchamber 112 or combustioncylinder 53. Pressure-relief valve 114, near the lower end of the bouncechamber 111, is provided for a purpose similar to that of relief valve113 on counterchamber 1 12.

Fuel injector 68 has been provided in combination with engine 50 toassure fuel admission which is precisely timed and which is directlyinitiated and sustained by the engine 50, as shown in FIG. 3.

As has been previously explained the continuous re-' liable operation ofa free-piston engine under varying load condition requires precisecontrol of combustion conditions. Proper timing, and fuel pressures, atthe time of fuel injection are important factors in this combustioncontrol so that the proper fuel quantity and dispersement are obtained.

Fuel injector 63 comprises a body portion 250 and a closure portion 251assembled with a gasket 252 impressed there between and held in place bysuitable means such as screws 253 positioned in counterbores 254. Bodyportion 250 is provided with a threaded insert portion 67 which isengaged in the head end 64 of combustion cylinder 53. Insert 67 isconstructed with an end surface 255 having a fuel nozzle 66 openingtherein.

Body portion 255 of fuel injector 68 is provided with a laterallydisposed bore 256 which terminates at one end in a wall with an aperture257. At the opposite end bore 256 is counterbored and threaded, andreceives an adjustable retainer screw 258. A plunger 259 is disposedwithin the bore 256 and is constructed to reciprocate therein in onedirection when actuated by pressure of rocker arm 142 upon plunger stem143. Operation of the plunger 259 in the opposite direction takes placeunder the urging of resilient means, such as compression spring 261 thatengages plunger 259 at one end and retainer screw 258 at the oppositeend.

An injector chamber 262 in the form of a counterbore having anupstanding passage-enclosing pedestal 263 is provided in the uppersurface of the body portion 250. An injection conduit 264 connects bore256 with fuel nozzle 66. At the opposite side, a chamber inlet passage283 connects bore 256 with chamber 262.

Cover portion 251 is provided with a pressure chamber 265 in the form ofa counterbore that is constructed to register with injection chamber262. Recesses 266 are provided at the edges of chambers 262 and 265 toreceive in assembly a diaphragm unit 267.

Diaphragm unit 267 comprises a centrally positioned flexible diaphragmmember 268 having fastened thereto at each side annular washers 269 andcentrally positioned pressure plates 270.

A diaphragm stop screw 271 is threadedly engaged in cover portion 251 inposition to contract upper pressure plate 270 of diaphragm unit 267. Theposition of contract is adjustable by means of rotation of the diaphragmstop 271 and a particular setting may be held by means of a lock nut272. Resilient means such as an injection chamber spring 273 ispositioned in the injection chamber 262 over pedestal 263. Spring 273engages lower pressure plate 270 at one end and the base of theinjection chamber 262 at the opposite end.

An inlet conduit 274 communicates with a fuel line 275 through aconventional tube connection 276. Inlet conduit 274 communicates withpressure chamber 265 in one branch 277 and with plunger bypass conduit278 in the other branch. Plunger bypass conduit 27 8 terminates in port280 at the lower side of bore 256-. A passage 281 provides communicationbetween a position opposite port 280 and chamber inlet passage 283.

Plunger 259 is provided with an annular groove 282 in the outer surfacethereof which is positioned to provide communication between port 280and passage 281 when plunger 259 is in the extreme right hand position,as shown in FIG. 3.

In the operation of the fuel injector 68, fuel is supplied underpressure through fuel line 275. Fuel line 275 is connected to a fueltank, designated generally as 290, and diagrammatically shown in FIG. 4.Fuel tank 290 comprises an upper accumulator portion 291 and a lowerstorage portion 292, which are hermetically sealed by a diaphragm 293.Accumulator section 291 is provided with a hand pump 294 and isconnected to accumulator line 128 from chamber 111 of engine 51).Storage portion 291 is provided with a fill spout 295 that is equippedwith a scalable cap 296.

In the normal operation of the engine, air in the accumulator portion291 is maintained at an elevated pressure by reason of the communicationestablished with bounce chamber 111 through line 123 and check valve130. The elevated pressure in chamber 291 deflects diaphragm 293downward putting the fuel under pressure. Pressurized fuel istransferred from tank 290 to fuel injector 68 through fuel line 275.

Fuel enters the fuel injector 68 through inlet conduit 294, passing topressure chamber 265 through passage 277 and to injection chamber 262through bypass conduit 278, groove 282, passage 281, and the upperportion of injection conduit 266. With the pressure equal on both sidesof the diaphragm, i.e., at the same fuel injection pressure, the forceof spring 273 keeps diaphragm unit 267 in its upper portion againstdiaphragm stop 281.

On the up stroke of piston 52, cam follower follows the bottom of camgroove 93 forcing actuator rod 139 radially outward in bore 59 againstthe urging of spring 145. Outward movement of actuator rod 139 operatesrocker arm 142 to force plunger stem 143 to the left, as shown in FIG.3. Plunger 259 is moved to the left by plunger stem 143 until groove 282aligns with injection conduit 264. The movement of groove 282 away fromport 280 operates as a valve closure in inlet fuel conduit 274 at port280; and injection chamber 262 is therefore sealed off from inlet fueland inlet fuel pressure. With injection conduit 264 open from injectionchamber 262 to nozzle 66 and with fuel in the pressure chamber 265 at ahigher pressure than the pressure in the combustion cylinder, the forceof spring 273- is overcome and diaphragm unit 262 moves downward forcingfuel from nozzle 66 into the combustion chamber.

The amount of fuel which is injected by the operation of the diaphragmdepends upon the displacement or stroke of the diaphragm, and this iscontrolled by means of adjustment in the position of diaphragm stop 271.

When piston 52 returns on the downstroke actuator rod spring 145 andplunger spring 261 return the plunger 259, rocker arm 142, and actuatorrod 139 to the starting position.

In normal operation, the injection cycle is repeated once for eachoperating cycle of the engine, continuously, and directly timed by theactuation of piston 52.

In order to start the engine it is necessary that the fuel bepressurized for the first injection. When operation commences pressurein chamber 111 will normally be atmospheric, and therefore, means suchas a hand pump: 294 is provided to pressurize the fuel injection systembefore the engine is started. When starting, it also may be necessary tooperate plunger 259 once manually by means of manipulation of rocker arm142 to assure that the injection chamber 262 is completely filled withfuel under pressure.

The diaphragm operated fuel injector 68 of this invention is actuateddirectly by piston '52 and utilizes reciprocal motion for its operation.In the free-piston engine 50, the motion delivered is reciprocating, andtherefore, the fuel injector 68 combines with the free-piston engine 50to provide continuous reliable operation and a clearly controlledcombustion cycle.

In addition, the compactness of the fuel injector 68 is an advantage inthat it increases the portability of the engine with which it iscombined.

Another form of a fuel injector that may be combined with thefree-piston engine 5t of this invention is designated generally as 350and shown in FIGS. 5 and 6. In general, fuel injector 350 comprises abody 351, a cover 352, a plunger 353, and resilient means 354, such asacompression spring.

Body 351 is constructed with a fuel-blast chamber 355, a pressureequalizer chamber 356, and a plunger chamber or bore 357. The blastchamber 355 is provided:

with a first conduit 358 for communication between the chamber 355 andthe bore 357. Blast chamber 355 is also provided with an equalizerconduit 359 at a position removed from conduit 358. The equalizerconduit 359 provides communication between chamber 355' and bore 357.Chamber 356 is provided with a passage 360 between the chamber 356 andan annular groove 36-1 in the wall of bore 357. Both chambers 355 and356 are closed by cover 352 which is held in place by suitable means,such as screws 362. A gasket 363 may be provided to assure that thechambers 355 and 356 are sealed from each other and from the atmosphere.

The plunger 353 is constructed to reciprocate between the extremeleft-hand position shown in FIG. and the extreme right-hand positionshown in FIG. 6. At one end, plunger 353 is provided with a stem 364 inoperative contact with rocker arm 142 of engine 56. At the opposite endspring 354 is disposed between the end of plunger 353 and the end ofbore 357. An aperture 365 is provided in the end of bore 357establishing communication between the atmosphere and the end of plunger353. Intermediate the ends of the body portion of plunger 353 areprovided a plurality of spaced passages 366 and 367.

Communication is provided between a fuel nozzle and bore 357 by a fuelinjection conduit 370.

A fuel inlet conduit 371 is provided from a fuel supply tube 372,through connection fitting 373, to a recess 374 at the bottom side ofbore 357. Fuel inlet conduit 371 is constructed to bypass blast chamber355 and is sealed therefrom. An air inlet conduit 375 is provided inbody portion 351 and cover 352 connected to air supply tube 376 by meansof fitting 377. Air supply conduit 375 connects with bore 357 through arecess 378 in the side there of and is constructed to bypass blastchamber 355, sealed therefrom.

In the free-piston engine 50 and fuel injector 350 combination, airsupply tube 376 is connected to an accumulator such as chamber 291 by aconventional tubing connection 377, and fuel supply tube 372 isconnected to a fuel tank 290, such as the tank shown in FIG. 4.

In operation of the fuel injector 350, spring 354 forces stem 364 andplunger 353 to the extreme right-hand position, shown in FIG. 6, on thedown stroke of the engine.

When piston 52 comes up on the compression stroke rocker arm 142 forcesplunger 353 to the extreme lefthand position, shown in FIG. 5, throughactuator rod 139 and cam follower 140 in cam groove 93.

When plunger 353 reaches the right-hand position,

pressurized fuel in inlet conduit 371, and recess 374 moves into fuelpassage 366. Simultaneously, pressurized air in air inlet conduit 375and recess 378, passes through passage 367 and conduit 358, and entersblast chamber 355. The air in blast chamber 355 is brought to a firstpressure P equal to that of the air in inlet tube 376. Equalizer chamber356 is in communication with the atmosphere through conduit 360, groove361, bore 357, and aperture 365.

7 As piston 52 moves upward on the compression stroke, plunger 353 movesto the left bringing passage 366 momentarily into a position of registrywith conduit 358 and fuel injection conduit 370. At this momentaryposition, air in chamber 355 at pressure P forces the fuel carried inpassage 366 downward through fuel injection passage 370 and out throughthe nozzle by blast effect. This blast eifect lowers the pressure in theblast chamber 355.

Continued travel to the left brings plunger 353 to the position shown inFIG. 5. In this position, passage 367 is aligned with conduit 359 andgroove 361. This brings blast chamber 355 into communication withequalizer chamber 356, allowing pressure to decrease in chamber 355 andto increase in chamber 356 until they are equal. The volumes of chambers355 and 356 are predetermined to be that which, in conjunction with theinlet air pressure and blast effect, will establish a pressure P inchamber 355 substantially equal to combustion cylinder 53 pressure atthe time fuel passage 366 registers with conduit 358 and conduit 370 onthe down or power stroke.

When the piston reverses and starts down, plunger 353 is urged and movesto the right by spring 354. At the time fuel passage 366 momentarilyregisters with conduit 358 and conduit 370, there is no air flow throughpassage 366 because of equal pressure conditions at both ends. Thisprevents the very bad problem of second injection which would occur ifthe pressure in chamber 355 were higher than the pressure in thecombustion cylinder 53 on the down stroke of piston 52. When plunger 353reaches its extreme righthand position again, as shown in FIG. 6, theinjection cycle is complete and ready for the next compression stroke.The injection cycle abovedescribed continues repeatedly once for eachcycle of engine 50.

Fuel injector 350 combines with engine 50 to provide a free-pistonengine in which fuel injection is positive and precisely timed withoutauxiliary equipment, such as an air compressor or rotary timing camshafts. The fuel injector 350 is operated directly from thereciprocating motion of the engine 50 and therefore utilizes thereciprocating motion of piston 52 without transformation to rotaryaction. A rotary motion mechanism for driving auxiliaries would increasethe size, cost, weight, and friction on engine 50.

Since fuel injector 350, utilizes the reciprocal motion of the engine50, the engine is more compact and is quieter. Compactness reducesweight and increases the portability of the engine, as well asincreasing the horsepower per pound of engine weight. In addition, theuseful power of the engine is increased as there is less loss infriction and power for the fuel injection auxiliary.

Another form of fuel injector, that is operable directly through thereciprocating motion of piston 52 in a freepiston engine 50, is shown inFIG. 7. Fuel injector 380 in general comprises a body portion 381, acover 382, a plunger 384, a needle valve 385, and an orifice tube 386.Body portion 381 and cover 382 are formed to be joined into a singleunit at mating surfaces 387. A chamber 388 is formed by the body 381 andcover 382 each being provided with a semicylindrical cavity therein. Agasket 389 is disposed between the surfaces 387, and is adapted to becompressed when cover 382 is fastened tight by suitable means, such asscrews 390.

Body 381 is provided with a lateral plunger bore 391 which connects atone end with a counterbore 392 of larger diameter. A compressed airsupply tube 393 is connected to an air inlet conduit 394 by means of asuitable fitting 395. Air conduit 394 intersects bore 391 at one side inan aperture 396. At the opposite side of bore 391, a chamber inletconduit 397 provides communication between bore 391 and chamber 388. Ata position removed from the entrance of chamber conduit 397, an outletpassage 398 provides communication between chamber 388 and bore 391.Outlet passage 398 continues from a position at the opposite side ofbore 391 to a fuel nozzle 399.

A fuel inlet tube 480 is connected to a fuel inlet conduit 401 by meansof a suitable fitting 482. Fuel inlet conduit bypasses chamber 388 andis constructed to communicate with the central bore of orifice tube 386at one end 403.

Needle valve 385 is threadedly engaged in body portion 381 in axialalignment with orifice tube 386 with the point of the needle 385 in theorifice end of tube 386.

Plunger 384 is provide with a plurality of annular grooved portions 404and 405 which are spaced from one another a distance greater than thedistance between inlet conduit 397 and the outlet conduit 398. At oneend, plunger 384 is provided with a stem portion 406 of lesser diameterwhich is adapted to receive a collar 407 retained in position against ashoulder 488 by suitable means such as a cotter pin 409. Resilientmeans, such as a spring 410, is disposed between the bottom ofcounterbore 392 and collar 407. A cap 411 is positioned on the stem 406and retained in position by rocker arm 142.

The fuel injector 380 is connected to frame 55 of engine 50 by means ofa threaded insert portion 412.

As in the previous form of fuel injector 350, compressed air inlet tube393 is connected to an accumulator, such as chamber 291, of fuel tank290, shown in FIG. 4. Fuel inlet tube 4% is connected to the fuel tank299'.

Rocker arm 142 is actuated to the left (in FIG. 7) on the up stroke andto the right on the down stroke of piston 52.

In FIG. 7, plunger 384 is shown at its extreme right hand position oftravel which is the position corresponding with the maximum downwardtravel of piston 52 in engine 59. Groove 4G4 aligns with conduits 396and 397 and air is forced by pressure across the end of orifice tube386. A quantity of fuel from fuel inlet conduit 401 is carried intochamber 388. The amount of fuel carried may be adjusted by means of thethreaded adjustment of needle valve 385. The fuel and air mixture swirlsin chamber 388 at a pressure P substantially equivalent to that of theinlet compressed air.

On the upward stroke of piston 52, rocker arm 142 forces plunger 384 tothe left bringing groove 405 into alignment with outlet 398 and movinggroove 404 out of alignment with conduits 396 and 397. When piston 52arrives at its position of maximum upward travel, groove 405 is properlyregistered and the fuel in chamber 388 is injected into combustionchamber 53 through fuel nozzle 399 by reason of the higher pressure P incha'mber 388 than that in combustion cylinder 53.

The movement of plunger 334 to the left compresses spring 410. Thiscompression of spring 410 returns plunger 384 to the position shown, asrocker arm 142 moves to the right on the down stroke of piston 52.

In another method of operation of fuel injector 380, the position ofgroove 405 is established with respect to the travel of plunger 384 sothat on the up stroke of piston 52 groove 405 passes to the left beyondregistry with conduit 398. This provides for an earlier fuel injectionon the up stroke of piston 52. In this method of operation, the size ofchamber 388 is determined in conjunction with the fuel injectionpressure and the cylinder compression pressure so that on the returnmovement of plunger 384 the pressure in chamber 388 and combustioncylinder 53 will be substantially equal. Therefore, no second injectionwill occur when groove 405 passes registry with conduit 398.

When piston 52 reaches its lower position, plunger 384 returns to itsextreme right-hand position, shown in FIG. 7, and the injection cycle iscomplete for one cycle of engine 50. The injection cycle repeatsconsecutively once for each complete cycle of engine 50 and under directand precise timing control from the operation of piston 52 and engine59. Fuel injector 38%) combines with engine 50 utilizing thereciprocating motion generated by the engine directly and a rotarymotion mechanism is not required. A rotary motion mechanism for drivingauxiliaries would increase cost, weight, size, and friction.

Since fuel injector 380 utilizes the reciprocating motion of the engine50, the engine is more compact and is quieter. Compactness reducesweight and increases the portability of the engine, as well asincreasing the horsepower per pound of engine weight. In addition, theuseful power of the engine is increased as there is less loss infriction and power for the fuel injection auxiliary.

It will be understood of course, that while the forms of the inventionherein shown and described, constitute preferred embodiments, it is notintended to illustrate all possible forms or ramifications of theinvention. It will also be understood that the words used are Words ofdescription rather than words of limitation and that various changes,such as changes in shape, size and arrangement of parts may be madewithout departing from the spirit and scope of the invention hereindisclosed.

What is claimed is:

1. In a free-piston engine having a cylinder, piston, and compressors, afuel injection system, comprising: a body member having a cavity forretaining pressurized fuel and having a discharge outlet in saidcylinder; a fuel container having a first chamber and a second cham ber;a flexible partition between said first chamber and said second chambercontaining fuel communication means between said compressor and saidfirst chamber whereby gas supplied from said compressor flexes saidpartition to pressurize said fuel; communication means between saidsecond chamber and said cavity for supplying pressurized fuel to saidcavity; a reciprocal plunger, having a conduit therein, disposed betweensaid cavity and said discharge outlet to provide intermittentcommunication between said cavity and said discharge outlet; andactuator means engaging said plunger and operable to reciprocate saidplunger.

2. In a free-piston engine having a cylinder, piston, and compressor, afuel injection system, comprising: a body member having a cavity forretaining pressurized fuel and having a discharge outlet in saidcylinder; a fuel container having a first chamber and a second chamber;a flexible partition between said first chamber and said second chambercontaining fuel communication means between said compressor and saidfirst chamber whereby gas supplied from said compressor flexes saidpartition to pressurize said fuel; communication means between saidsecond chamber and said cavity for supplying pressurized fuel to saidcavity; a reciprocal plunger, having a conduit therein, disposed betweensaid cavity and said discharge outlet to provide intermittentcommunication between said cavity and said discharge outlet; alongitudinal cam groove provided on said piston; a cam follower incontact with said cam groove; and a rocker arm engaging said camfollower and said plunger whereby, on reciprocation of said piston, saidcam groove, cam follower and rocker arm cooperate to providereciprocating motion to said plunger.

3. A fuel injector for internal-combustion engines having a combustioncylinder comprising: a body member having a discharge outlet in saidcombustion cylinder and being formed with a plurality of recesses; aplunger reciprocable in one of the recesses in said body member;resilient means disposed in said body member urging said plunger inmovement in one direction; actuator means engaging said plunger memberand operable to move said plunger in the opposite direction; a diaphragmpartitioning another of said recesses into a first and a second chamber;resilient means in said first chamber urging said diaphragm toward saidsecond chamber; means for supplying fuel at a first pressure to saidsecond chamber and to said plunger recess; communication means betweensaid first chamber and said plunger recess, and between said plungerrecess and said fuel discharge outlet; and conduit means in saidplunger, said conduit means in reciprocation of said plunger alternatelyregistering with said supply means and communication means, andalternating the pressure in said first chamber between said firstpressure and the pressure of said combustion cylinmember having adischarge outlet in said combustion cylinder and being formed with aplurality of recesses; a plunger reciprocable in one of the recesses insaid body member; resilient means disposed in said body member urgingsaid plunger in movement in one direction; a

longitudinal cam groove provided on said piston; a cam follower incontact with said cam groove; a rocker arm engaging said cam followerand said plunger whereby on reciprocation of said piston, said camgroove, cam follower, and rocker arm cooperate to force said plungeragainst said urging of said resilient means providing reciprocatingmotion to said plunger; diaphragm partitioning another of said recessesinto a first and a second chamber; resilient means in said first chamberurging said diaphragm toward said second chamber; means for supplyingfuel at a first pressure to said second chamber and to said plungerrecess; communication means between said first chamber and said plungerrecess, and between said plunger recess and said fuel discharge outlet;and conduit means in said plunger, said conduit means in reciprocationof said plunger alternately registering with said supply means andcommunication means, and alternating the pressure in said first chamberbetween said first pressure and the pressure of said combustioncylinder; said alternating pressure flexing said diaphragm to injectfuel into said combustion cylinder.

6. In a free-piston-engine compressor having a cylinder and piston, afuel-injection system comprising: a body member having a dischargeoutlet in said combustion cylinder and being formed with a plurality ofrecesses; a plunger reciprocable in one of the recesses in said bodymember; resilient means disposed in said body member urging said plungerin movement in one direction; a longitudinal cam groove provided on saidpiston; a cam follower in contact with said cam groove; a rocker armengaging said cam follower and said plunger whereby on reciprocation ofsaid piston, said cam groove, cam follower, and rocker arm cooperate toforce said plunger against said urging of said resilient means providingreciprocating motion to said plunger; a diaphragm partitioning anotherof said recesses into a first and a second chamber; resilient means insaid first chamber unging said diaphragm toward said second chamber; afuel container having a gas chamber and a fuel chamber; a flexiblepartition between said gas and fuel chambers; communication meansbetween said compressor and said gas chamber whereby gas supplied fromsaid compressor flexes said partition to pressurize fuel in said fuelchamber; communication means between said fuel chamber and said secondchamber for supplying fuel at a first pressure to said second chamberand to said plunger recess; communication means between said firstchamber and said plunger recess, and between said plunger recess andsaid fuel discharge outlet; and conduit means in said plunger, saidconduit means in reciprocation of said plunger alternately registeringwith said supply means and communication means, and alternating thepressure in said first chamber between said first pressure and thepressure of said combustion cylinder; said alternating pressure flexingsaid diaphragm to inject fuel into said combustion cylinder.

7. A fuel-injector system in a free-piston engine compressor accordingto claim 6 wherein stop means is provided in said first and secondchambers controlling the flexture of said diaphragm and the quantity offuel injected.

8. A fuel injector for internal-combustion engines having a combustioncylinder comprising: a body member having a discharge outlet in saidcombustion cylinder and being formed with a plurality of chambers; aplunger valve reciprocable in a bore in said body member; resilientmeans disposed in said body member urging said plunger in movement inone direction; actuator means engaging said plunger and operable to movesaid plunger in the opposite direction; means for supplying air to saidplunger bore at superatmospheric pressure; means for supplying fuel tosaid plunger bore at said pressure; communication means between a firstone of said chambers and said plunger bore; communication means betweensaid discharge outlet and said plunger bore; communication means i2between a second one of said chambers and said plunger bore; and a firstand second conduit in said plunger, said first conduit in reciprocationof said plunger sequentially registering with said fuel supply means ata first position, between said first chamber communication means andsaid discharge outlet communication means at a second position, and withsaid plunger bore at a third position, said second conduit sequentiallyregistering between said first chamber communication means and said airsupply means at said first position, with said plunger bore at saidsecond position, between said first chamber communication means and saidsecond chamber communication means at said third position, said secondchamber communication means being open to the atmosphere at said firstposition.

9. A fuel injector for internal-combustion engines according to claim 8wherein said first and third positions are terminal positions in saidreciprocation of said plunger.

10. In a free-piston-engine compressor having a cylinder and piston, afuel injection system, comprising: a body member having a dischargeoutlet in said combustion cylinder and being formed with a plurality ofchambers; a plunger valve reciprocable in a bore in said body member;resilient means disposed in said body member urging said plunger inmovement in one direction; a longitudinal cam groove provided on saidpiston; a cam follower in contact with said cam groove; a rocker armengaging said cam follower and said plunger whereby on reciprocation ofsaid piston, said cam groove, cam follower, and rocker arm cooperate toforce said plunger against said urging of said resilient means providingreciprocating motion to said plunger; a fuel container having an airchamber and a fuel chamber; a flexible partition between said airchamber and said fuel chamber; communication means between saidcompressor and said air chamber whereby air supplied from saidcompressor flexes said partition to pressurize fuel in said fuelchamber; communication means between said fuel chamber and said plungerbore for supplying fuel to said plunger bore at superatmosphericpressure; communication means between said compressor and said plungerbore for supplying air to said plunger bore at said pressure;communication means between a first one of said chambers and saidplunger bore; communication means between said discharge outlet and saidplunger bore; communication means between a second one of said chambersand said plunger bore; and a first and second conduit in said plunger,said first conduit in reciprocation of said plunger sequentiallyregistering with said fuel supply means at a first position, betweensaid first chamber communication means and said discharge outletcommunication means at a second position, and with said plunger bore ata third position, said second conduit sequentially registering betweensaid first chamber communication means and said air supply means at saidfirst position, with said plunger bore at said second position, betweensaid first chamber communication means and said second chambercommunication means at said third position, said second chambercommunication means being open to the atmosphere at said first position.

11. A fuel injector for internal-combustion engines having a combustioncylinder comprising: a body member having a discharge outlet in saidcombustion cylinder and being formed with a chamber therein; a plungerreciprocable in a bore in said body member; resilient means disposed insaid frame urging said plunger in movement in one direction; actuatormeans engaging said plunger and operable to move said plunger in theopposite direction; means for supplying air to said plunger bore atsuperatmospheric pressure; means for supplying fuel at said pressure tosaid air supply means; means in said air sup ply mean for controllingfuel flow to said bore; communication means between said plunger boreand said chamber; communication means between said bore and saiddischarge outlet; and first and second conduits in said plunger, saidfirst conduit in reciprocation registering with said air supply meansand said chamber communication means at one position of said plunger,said second conduit registering with said chamber communication meansand said discharge outlet communication means at a second position ofsaid plunger, the registration of said first and second conduitsalternating with the reciprocation of said plunger.

12, A fuel injector according to claim 11 wherein said fuel controlmeans comprises an orifice and coacting needle valve.

13. In a free-piston engine compressor having a cylinder and piston, afuel-injection system, comprising: a body member having a dischargeoutlet in said combustion cylinder and being formed with a chambertherein; 15 a plunger reciprocable in a bore in said body member;resilient means disposed in said frame urging said plunger in movementin one direction; a longitudinal cam groove provided on said piston; acam follower in contact with said cam groove; a rocker arm engaging saidcam follower and said plunger whereby on reciprocation of said piston,said cam groove, cam follower, and rocker arm cooperate to force saidplunger against said urging of said resilient means providingreciprocating motion to said plunger; an air supply line from saidcompressor to said plunger bore providing air at superatmosphericpressure to said bore; a fuel container having an air chamber and a fuelchamber; a flexible partition between said air chamber and said fuelchamber; communication means between said compressor and said airchamber whereby air from said compressor flexes said partition topressurize said fuel in said fuel chambers; communication meansbetweensaid fuel chamber and said air supply line for supplying fuel tosaid air supply line at superatmospheric pressure; means in said airsupply line for controlling fuel flow to said bore; communication meansbetween said plunger bore and said chamber; communication means betweensaid bore and said discharge outlet; and first and second conduits insaid plunger valve, said first conduit in reciprocation registering withsaid air supply means and said chamber communication means at oneposition of said plunger, said second conduit registering with saidchamber communication means and said dis charge outlet communicationmeans at a second position of said plunger, the registration of saidfirst and second conduits alternating with the reciprocation of saidplunger.

14. A fuel-injector system in a free-piston compressor according toclaim 13 wherein said fuel control means comprises an orifice and aneedle valve.

15. In a free-piston engine having a cylinder, piston, 5 and compressor,a fuel injection system, comprising: a body member having a cavity forretaining pressurized fuel and having a discharge outlet in saidcylinder; a fuel container having first communication means between saidcompressor and said fuel container and second communication meansbetween said container and said cavity whereby gas supplied from saidcompressor pressurizes said fuel; a reciprocal plunger, having a conduittherein, disposed between said cavity and said discharge outlet toprovide intermittent communication between said cavity and saiddischarge outlet; and actuator means engaging said plunger and operableto reciprocate said plunger.

16. In a free-piston engine having a cylinder, piston, and compressor, afuel injection system, comprising: a body member having a cavity forretaining pressurized fuel and having a discharge outlet in saidcylinder; a fuel container having a first chamber and a second chamber;a flexible partition between said first chamber and said second chambercontaining fuel communication means between said compressor and saidfirst chamber whereby gas supplied from said compressor flexes saidpartition to pressurize said fuel; communication means between saidsecond chamber and said cavity for supplying pressurized fuel to saidcavity; a reciprocal plunger,

having a conduit therein, disposed between said cavity and saiddischarge outlet to provide intermittent communication between saidcavity and said discharge outlet; and actuator means responsive tomovements of said piston engaging said plunger and operable toreciprocate said plunger.

17. In a free-piston engine compressor having a cylinder and piston, afuel injection system comprising: a body member having a dischargeoutlet in said combustion cylinder and being formed with a plurality ofrecesses; a plunger reciprocable in one of the recesses in said bodymember; resilient means disposed in said body member urging said plungerin movement in one direction; an actuator means responsive to movementsof said piston engaging said plunger to force said plunger against saidurging of said resilient means providing reciprocating motion to saidplunger; a diaphragm partitioning another of said recesses into a firstand a second chamber; resilient means in said first chamber urging saiddiaphragm toward said second chamber; a fuel container having a gaschamber and a fuel chamber; a flexible partition between said gas andfuel chambers; communication means between said compressor and said gaschamber whereby gas supplied from said compressor flexes said partitionto pressurize fuel in said fuel chamber; communication means betweensaid fuel chamber and said second chamber for supplying fuel at a firstpressure to said second chamber and to said plunger recess;communication means bet-ween said first chamber and said plunger recess,and between said plunger recess and said fuel discharge outlet; andconduit means in said plunger, said conduit means in reciprocation ofsaid plunger alternately registering with said supply means andcommunication means, and alternating the pressure in said first chamberbetween said first pressure and the pressure of said combustioncylinder, said alternating pressure flexing said diaphragm to injectfuel into said combustion cylinder.

18. In a free-piston engine compressor having a cylinder and piston, afuel injection system, comprising: a body member having a dischargeoutlet in said combustion cylinder and being formed with a plurality ofchambers; a plunger valve reciprocable in a bore in said body member;resilient means disposed in said body member urging said plunger inmovement in one direction; and actuator means responsive to movement ofsaid piston engaging said plunger to force said plunger against saidurging of said resilient means providing reciprocating motion to saidplunger; a fuel container having an air chamber and a fuel chamber; aflexible partition between said air chamber and said fuel chamber;communication means between said compressor and said air chamber wherebyair supplied from said compressor flexes said partition to pressurizefuel in said fuel chamber; communication means between said fuel chamberand said plunger bore for supplying fuel to said plunger bore atsuperatmospheric pressure; communication means between compressor andsaid plunger bore for supplying air to said plunger bore at saidpressure; communication means between a first one of said chambers andsaid plunger bore; communication means between said discharge outlet andsaid plunger bore; communication means between a second one of saidchambers and said plunger bore; and a first and second conduit in saidplunger, said first conduit in reciprocation of said plungersequentially registering with said fuel supply means at a firstposition, between said first chamber communication means and saiddischarge outlet communication means at a second position, and with saidplunger bore at a third position, said second conduit sequentiallyregistering between said first chamber communication means and said airsupply means at said first position, with said plunger bore at saidsecond position, between said first chamber communication means and saidsecond chamber communication means at said third 1 5 position, saidsecond chamber communication means being open to the atmosphere at saidfirst position.

19. In a free-piston engine compressor having a cylinder and piston, afuel injection system, comprising: a body member having a dischargeoutlet in said combustion cylinder and being formed with a chambertherein; a plunger reciprocable in a bore in said body member; resilientmeans disposed in said frame urging said plunger in movement in onedirection; an actuator means responsive to movements of said pistonengaging said plunger to force said plunger against said urging of saidresilient means providing reciprocating motion to said plunger; an airsupply line from said compressor to said plunger bore providing air atsuperatmospheric pressure to said bore; a fuel container having a firstcommunication means between said compressor and said fuel container andsecond communication means between said fuel container and said airsupply line whereby said compressor pressurizes said fuel therebysupplying fuel to said air supply line at super- I? atmosphericpressure; means in said air supply line for controlling fuel flow tosaid bore; communication means between said plunger bore and saidchamber; communication means between said bore and said dischargeoutlet; and first and second conduits in said plunger valve, said firstconduit in reciprocation registering with said air supply means and saidchamber communication means at one position of said plunger, said secondconduit registering with said chamber communication means and saiddischarge outlet communication means at a second position of saidplunger, the registration of said first and second conduits alternatingwith the reciprocation of said plunger.

References Cited in the file of this patent UNITED STATES PATENTS2,447,513 Lewis Aug. 24, 1948 2,779,156 Huber Jan. 29, 1951 2,804,856Spurlin Sept. 3, 1957

